*{
    padding:0px;
    margin: 0px;
}
html,body,#app{
    width: 100%;
    height: 100%;
}
.main{
    min-width: 320px;
    max-width: 640px;
    width: 640px;
    margin:0 auto;
}
.fl {
    float: left;
}
.fr{
    float: right;
}
.clearfix::after{
    content: "";
    clear: both;
    display: block;
}
ul,ol{
    list-style: none;
}

